The move, which was retroactive to last Wednesday, came a week after right-hander Marcus Stroman went on the DL due to right shoulder fatigue.
The Blue Jays recalled right-hander Deck McGuire from triple-A Buffalo and pencilled in recent call-ups Sam Gaviglio and Joe Biagini to start games against Oakland over the weekend.
Garcia has struggled this year with a 2-3 record and 6.28 earned-run average over eight starts.
Blue Jays manager John Gibbons said Garcia’s shoulder "flared up again" a couple days ago.
"It’s no big deal," Gibbons said before Friday’s game against the Athletics. "Just a little inflammation. Figure he’ll miss a start and he should be fine."
Garcia, who signed a US$8-million, one-year deal in the off-season, was shelled for six runs in 3 2/3 innings last Tuesday in a 12-2 loss to the New York Mets.
The 31-year-old has a career mark of 69-58 with a 3.78 ERA over parts of 10 big-league seasons.
McGuire, 28, was 3-1 with a 2.70 ERA over five starts with the Bisons. The six-foot-six right-hander made one appearance for the Blue Jays earlier this season, giving up three earned runs over 3 1/3 innings.
Gibbons also said that outfielder Teoscar Hernandez could return to the lineup Saturday afternoon. He skipped Thursday’s game due to back tightness.